Certain gas/liquid separation assemblies, for example as used with air compressors, include two general components: a vessel with a cover, and a removable and replaceable (i.e., serviceable) separator element unit, construction or arrangement. In some assemblies a single (one) serviceable separator element is used as the separator element construction; in others, multiple serviceable elements are used. In general, operation involves directing a gas/liquid flow into the vessel. The gas flow is eventually directed through the serviceable separator unit, i.e., through the serviceable separator element or elements. With passage through the separator unit, liquid coalescing and drainage occurs. As a result, an entrained liquid concentration, within the gas stream, is reduced. Periodically, the serviceable element(s) are removed and replaced.